Dynamometer



Aug. 24,1926.

J. B. DAVIDSON ET AL DYNAMOMETER Filed June 1e. 1924 2 sheets-Sheet 1wkw Aug. 24 1926. 1,597,064

J. B. DAVIDSON ET AL DYNAMOMETER Filed June 16, 1924 2 Sheets-Sheet 2www Patented Aug. 24, 1926.

UNI-reu STA TESn PATENT JAY BROWNLEEDAVDSON AND EDGAR v. coLLnsj, onAMES, IQWA, esslqlots To lIOWA STATE ooLLneE'or AGnrcULTURE'AnDIJLECHANIC Anita oEAMEsj, Iowa,

A CORPORATION OF IOWA.

DYNAMOMETER.

Application led .Tune 16, 1924. SerialNo. 720,363.

lThe object of our invention. is to providey a dynamo'meter of.' simple,durable and inexpensive construction for testing-in a. confv any primemover, such for instance as an.

internal combustion engine, which applies its. power through a rotarymovement such for instance asby means of a pulley.

Our invention. consists .in the construction, arrangement and;vcombinationbtV the various. parts of: the device, wherebyY the objects`contemplated are attained, as 'hereinafter more` fully -set-v forth,pointed out in our claims, Vand illustrated in the..accompany iug-ydrawings, in whichy Figure 1 showsV a'top..for plan view of adynainometer embodying. our invention.

Figure 2'shows, a vertical, sectional View of same on the line 2.-:2: ofFigure 1, with the weights partly elevated and the valve slightlyV openAas in, use under certain conditions. A

Figure 3; shows a horizontal, sectional view. on the line 3*-3 otFigure2;

Figure 4 shows a vertical, sectional viewl on theline 1 -t ofFigure`1;-. and

Figure 5L shows a verticali sectional view of the valve device initsfully openedV posi-Y tion. Referring to the accompanying drawings, wehave used the reference.' numeral 10 to indicate t-he tank orreceptaclein whichv the dynamometer is mou-nted. Resting on the bottomoffthe tank are the supporting legs 11 fixed in position by the bolts12.

rlihedynamometer casing is indicated generally by the reference numeral13. This casing is tiltingly supported by means of the trunnions 14projectedV outwardlyifrom it and mounted for. rockingmovement upon theupper ends of the legs 11. Vithin the` casing there is a chamber 15.having the usual contour' of a rotaryV p.ump,and adjacent to the rotarypuin-p chamber is a second chamber in which. there. .is rotatively.mounted two intermeshing cog wheels .1.6. VV'ithin the chamber 15therefare twov coacting ro-` tary impellers 17,-.'one of which ismounted upon the .driven shaft 18 which is also liXed to the adjacentone of the'cogl wheels 16, and the other vi's mounted upon the driving.-shaft 19.which is also ed tothe other of the cog lixedtoits outer endi.

vCommunicating. with the interijc'i'rll off the chamber 15 is anc intakeport devia-"1,21Y ar ranged to discharge ina radial) direction t0- ward.the center of the shaft- 1f9 llieadifrigl from the upper portion ofthech-amber` 1 5 is.'

a discharge port device 22 whichy is pro*- vided: at its outerI endlW'ithia vertically/an rangedV cylindrical valvemember 23 ,Open at both.ends. Mountedlin the valve member 23 is a coacting valve member 24capable of vertical movement, closed.i at its upper lend andlopen' atitslower end` and provided?.r

near .its central portion -with a series of# perforationsl 25 those nearthe upperend preterably being. smaller than the ones below. Pivot'edtothe lower end' of the valve member 24 is a link 26 extendeddovvnwafrdl'y, and pivoted in turn to support 26a secured to the bottomof the tan-kl-O;

Fixed to the casing 1 3 at they end opposite from the valve member is abeam 27 which. extends! through the taI1k-10andis provided at its'outerendl with anarcuate head 2722 Fixed to the top of this, arcuate head isa flexible rod 2,7b 'and' attached to thelower end ofV the rodV 27? is arod 28 upon which a weight 29 is` mounted. The tank is partly iilledwith liquid 30, asV shown in Figure 2.

In practical operation and assuming'thatit is desire-d to ascertain theVmaximum pulling power of a prime mover suchv for instance Aas aninternal combustion engine, then the prime mover is belted to the pulley26 and started in such a direction that the i-inpellers 17 will move inthe direction ind-icated by the arrows in Figure 2. Beforey the power isapplied to the pulley 20, the weight 29 will be at its lower limit ofmovement and the valve device will be in theA position shownin Figureel. That, is to say,

it will be closed. When in thisrposition,v

the impellers will be locked against rotation by the liquid containedwithin the chamber 15, and hence since the impelljers cannot rotate whenin this positiom the power apr.y

plied to. the pulley 20 will first be utilized in tiltin the Icasingfl.n This tilting movement wi l1 loe opposed by the weight 29, and

hence the device will not tilt until the torque applied to the pulley 2Ois sui'licient to impart such tilting movement to the casing 13 as toelevate the weight 29.

l/Vhen the weight commences to elevate, the valve device will lirstassume a partially opened position, as shown in Figure 2, and when thisposition is reached, then the impellers may rotate in unison with thhepulley 20, and a current or' liquid will be discharged through the valveinto the tank and from the tank into the rotary pump chamber l5. As thetorque applied to the pulley 2O is increased, the weights will beelevated and the valve device more widely opened, as shown in Figure 5.Obviously, as the valve device approaches its wide open position, lessresistance is applied by the impellers to the casing 13, ina directiontending to open the valve, and hence the gravity pull of the weightswill tend to partially close the valve device. v

During the continued operation of thel prime `mover at a certain speed,a balanced position will be established between'these two opposi-ngforces, and when this balance has been ellected, the pulling` power ofthe prime mover may be accurately determined by the amount oi theweight. lt the test is being made when the prime mover is running at arelatively high` speed, the device will be tilted to position foropening the valve device relatively wide, and when the test is beingapplied to a prime mover running at a relatively low speed, the valve device will automatically remain in a relatively restricted position.

In making a test of this character, and in the event it is desired todetermine the pull ing power of the prime mover, when operating asdistinguished from its pulling power at the start, then the operator maysimply elevate the weight beam until the desired speed has beenattained.

By having the intake port device ar-r ranged radially relative to thedrive shaft, the impact of incoming currents of liquid is neutralizedand has no tendency to tilt the casing in either direction. By having anarc on the end of the weight beam 27 ar ranged concentric to the drivingshaft, and. by having the weight supported by a ilexi- V ble rodengaging the arcuate head of the beam it is obvious that the gravitypull of the weights attached to its cuter end will be substantially thesame when the beam is in any or its va ions positions olf movement.

VBy having theV casing provided with trunnions and mounted in suitablebearings, the friction caused by its tilting movements is reduced to anegligible quantity for the purpose intended, and by having the drivingshaft mounted in the casing and arranged to rotate in the directionshown, any friction between the drive shaft and its bearing will beapplied to the tilting casing in the proper direction, and will notten-d to alter or at feet the accuracy ot the test being made.

The device will not be aii'ected by heatV through a wide range at thewill of theop-A erator, by attaching or removing weights.

Furthermore, eXtreme accuracy7 1n the test is secured, because the.balancing 1s automatic and the trictional loss is negligible.

rihe liquid within the pump casing, when acted upon by the impellercontained withinthe casing, providesy means for opening the valve onaccount of its action tending to tilt the casing when the valve isclosed, or partly closed. The beam and weight constitute a resistancedevice operatively connected tothe valve device lor opposing the openingmovement oli' thevalve device. Obviously a spring may be substituted inplace of the weight.

YWe claim as our invention:

l. in a dynamometer, the combination of a tiltable casing, an impellerdevice therein so arranged that liquid will be positively driven therebythrough the. casing when the impeller device is rotated, means forrotating the impeller device, a yielding pressure device applied to thecasing for tilting it in one direction, and a valve device forcontrolling the passage of liquid through the casing, one member of thevalve device being connected to the casing and the other member beingconnected to a stationary support, said valve device being so arrangedand combined that when the casing is tilted in the direction opposingthe force exerted by the yielding pressure device, the valve will beopened, and when the casing is tilted in the opposite direction thevalve will be closed.

'2. In a dynamommeter, the combination ol a tiltable casing, an impellerdevice therein so arranged that liquid will be positively driven therebythrough the casing when the impeller device is rotated, means forrotating the impeller device, a yieldable pressure device applied to thecasing for tilting it in one direction, and a valve device forcontrolling the passage of liquid through the casing, said valve devicecomprising a valve member lixed to thecasing and communicating with theinterior of the casing, a sliding member so arranged that in onedirection it will close the passage from the casing, and

in its other position it will permit the contents of the casingl to passout through the valve, and a link connected to Said sliding valve memberand to a stationary support.

3. A dynamometer, comprising a tank for containing liquid, bearingsmounted in the tank, a casing formed with trunnions tilt-ably mounted insaid bearings, a driving shat extended through-the casing concentricWith said trunnions, an impeller device Within the casing comprising adriving impeller member and a driven impeller member, said casing beingformed With an intake passageway arranged radially to the driving shaft,said casing also being formed With a discharge .passageway having at itsouter end an upright tubular valve member, a coacting tubular valvemember slidingly mounted' therein open at its bottom and formed with aseries of openings of different sizes formed in the side Walls of thesaid sliding valve member so positioned that one or more of them maycommunicate With the said discharge passageway from the casing dependingonthe. position of the sliding valve member Within the upright tubularvalve member, a link pivotally connected to the said sliding valvemember and extended downwardly and connected to a stationary support,and a beam iXed to the casing and eX- tended in a direction radial tothe driving shaft, and a Weight device on said beam, sub-y stantiallTas` and for the purposes stated.

JAY BROWNLEE DAVIDSON. EDGAR v. COLLINS.

